Tool grinder



y 1938- -A. o. $CHAEFER 2,124,592

TOOL GRINDER Filed July 24, 1936 4 Sheets-Sheet 1 INVENTOR.

July 26, 1938. o. SCHA-EFER TOOL GRINDER Filed July 24, 1936 4 Sheets-Sheet 2 INVENTOR. 44/040 0564M? A T NEYS.

ly 26, 1938- A. o; SCHAEFER 2,124,592

TOOL GRINDER Filed July 24, 1936 4 SheetE-Sheet 3 INVENTOR,

July 26, 1938. A. o. scHAEFER TOOL GRINDER Filed July 24, 1936 4 Sheets-Sheet 4 INVENTOR. fldo/ ob 0 561706 42;

Patented July 26,' 1938 UNITED STATES PATENT OFFICE I 2,124,592 1 TOOL GRINDER v Adolph 0. Schaefer, Brooklyn, N. Y., assignor to Atlantic Service Company, Inc., Brooklyn, N. Y., a corporation of New York Application July 24, 1936, Serial No. 92,272

4 Claims.

This invention relates to a tool sharpener or to machines for sharpening or polishing tools and the like and it has for an object to provide a machine of the abrasive belt type which is compact, in which the moving parts are all enclosed, which is adjustable for work of different sizes and shapes and which will polish a surface or grind a fine edge on bothsides of the tool.

The machine comprises a base plate upon which a pair of frames are pivotally mounted and are angularly adjustable relative to each other. These frames form a housing for the belt pulleys and the abrasive belts so that no part of the moving mechanism is exposed except the portion of the belt that is used for polishing. The belts are driven in the same direction and at the same speed by the frictional engagement of a pair of pulleys carrying the belts and one of these pulleys is driven by a motor or other source of power.

The frames are inclined at an angle to each other with the lower pulleys of each frame in contact. This brings the belts in contact with each other and the tool to be sharpened is in-' serted between the belts so that it is ground on both sides and it is ground to an edge that, theoretically, tapers off to infinity as it approaches the point of contact of the rollers. The rollers are held in engagement by the action of a spring and the rollers themselves have a tire of rubber which is relatively soft and yielding.- The rubber tired pulley or roller makes the friction drive practical and it provides the driving friction for the abrasive belts. Other objects of the invention reside in the construction of the apparatus and the arrangement of the parts as more fully described in the following specification and illustrated in the accompanying drawings, in which Fig. l is a vertical elevation of the machine from the front with the covers of each frame.

removed;

Fig. 2 is a view of part of the cover for one of the frames;

Fig. 3 is a rear elevation of the machine complete with certain parts sectioned;

Fig. 4 is a vertical cross section on the line 44 of Fig. 3;

Fig. 5 is a vertical section through the base and frame on line 5-5 of Fig. 3;

Fig. 6 is an indexing arrangement applied to the front cover to indicate the angular deflection of the frame;

Fig. 7 is a diagram showing the engagement of the rubber tired rollers with relation to the edge of the tool to be sharpened; V

Fig. 8 is a plan view of a pair of rollers made with matched corrugated faces that may be used for driving the abrasive belts, and

Fig. 9 is another form of roller provided with spiral grooves on its face.

In the drawings I I is a vertical base plate which is provided with a horizontal leg at l2 to act as a stand. l3 is'one of the frames and I4 is the other frame which are mounted side by side against the base II as hereafter described. The frame 13 has an upper pulley l5, mounted on the shaft I6 and thelower pulley 11, mounted on the shaft i8 and provided with a rubber tire or tread l9. On this pair of pulleys the abrasive belt is mounted. The structure of frame I4 corresponds with frame I3 with the pulley 2| mounted on shaft 22 at the top and pulley 23 having the rubber tire 25; mounted on shaft 24 at thebottom and with the abrasive belt 26 mounted on this pair of pulleys. Each frame is provided with a cover 29 which is secured by the knurled'nut 32, Fig. 4, on the stem 3| and by the dowels 28. Each cover has a bent over wing 30, shown in section in Fig. 1 which encloses the belt opposite the upper pulleys and exposes the face of each belt belowthese pulleys down to the engaging point of the lower pulleys at a. In this arrangement it will be noted that the pulleys and the abrasive belts are completely enclosed by the hollow frame and the cover therefor except the grinding portion of the belts and the operator is protected in using the machine. The hollow frames are readily removable from the base.

The tool to be sharpened or-polished is indicated at 21, Figs. 1 and '7 and is drawn back and forth across the face of the moving belts during the operation.v This'sharpens each side of the blade or knife to the same extent.

A lug 35 is provided on frame l4, Fig. 3, to which the arm 36 is pivoted by the stud 31. This arm is moved upwards by a bias due to spring 38 connected to the fixed lug 39 on the frame I4.

7 The arm 36 has screwed therein the stem of shaft 22 which carries the pulley 2| and this stem is locked against the collar 22a on shaft 22 by the knurled nut 43. .The collar 22a moves vertically in the slot 4| in the frame I4.

By this arrangement it will be noted that the spring 38 applies and maintains tension on the abrasive belt 26 and by pressing ,the knob 40 downward the tension is released and the belt may be removed.

The construction of frame I3 corresponds with frame Hi just described in which the arm 43 is pivoted at, 44 to the lug 42 and is biased up- 2f 5 Wards by thespring 65 engaging the lug 46. The knob 41 is attached to the shaft l6 of the upper pulley I5 and through the slot 48 enables this pulley to be raised or lowered as desired. 1 The cam 49 and lever 50 may be used for this purpose.

The frame I4 is secured to the base II by I means of the stud 52 which passes through the slot 55engaging theframe I4.

.is similarly secured to the base H by the "stud 51in theslot 58 engaged by the nut 56. and

slot 53 and is locked in position by the knurled nut'5l. The frame is also secured to the base at the lower end, through the stud 54 in the by the stud 59 in slot' 60. ..'Ihe sl0ts53'and55 are 'arcuate shaped and are centered about the pivot of'the frame; also the slots 58 and 60 are arcuate shaped centered about the pivot of frame l3. V An aperture ismade in the base II at 6| 'exposing the'iframe'M uponwhich thearmliZ is mounted by the stud 63 of the stem'Bl in the boss 82,.Figp4. The lower end of arm 62 has screwed'therein thestemof shaft 24 upon which 7 the roller 23 ismounted. This stem has a collarZtafengaging arm 62 on one side and the knurled. nut 64nengagingthe arm on the opposite sides The collar 24a is free to move in the.

: tion in which the-pulleys are disengaged and against the action of spring .61. "This comprises the plunger 10 engaging an aperture H in the frame 14 whemthe armi62 is moved to the disengaged position. A. flat spring 69 forces the.

plunger '10 into the latching notch in Hi. When the plunger lfl'is released the engagement of pulleys" and His restored. It should be noted onjthe base plate ll so that they pivot about that the arm 62 moves at both ends'relative to the base I I. If the aperture 6| were not provided-in the base two slots would. be required" to permit this movement. The aperture 6| enables the arm to be'placed against the frame and flush with the base l.. This shortens the stud connectionsto the arm andthe base ll protects it against accidental movement. r

The frames l3 and M are pivotally mounted the axis of the rollers Hand 23 and may be brought close together as indicated in Fig. 1 or they may bespread. apart as indicated in Fig.3, but in'each "casethe-relation of therollers I land 23to each other is not changed. This construction is provided for by a socket formed in the base 'H on the axial line of the rollers l1 and 24 and bya stem on each frame matching with the corresponding socket and upon which the framesare maintained in alignment to each other. 7

Fig. 5 illustrates the drive in the socket and stem arrangement for the frame Hi from which it will be noted that the frame-is provided with a hollow. stem '15 passing through a socket or aperture in the base II and by means of which n the frame l3 may be rotated on its support H, the extent of the rotation is determined by the The frame l3 gages the slots 58 and 60 andthe'frame is locked in the desired position by the nut 56 The drive is obtained through the grooved pulley 12, mounted on shaft 13, in the hollow stem 15, which is pro- 4, commatched socket or groove in the base H and upon which the frame I4 is pivotally adjusted. It

.Will be noted that this socket arrangement leaves "the shaft 24 of the pulley 23 free'tojbe adjusted "inythe slot 65 While the frame may be rotated to any position; 'Both-the frames can readily be adjustedfto the same'angular position on the base by the use of the index, Fig. 6, in which 7 In the pivotal mounting of the rollers and the frames in the base II, it will be observed that the stud bearings of the rollers leave theirends open so that the belts can be replaced without taking the mechanism apart; also that a frame may be the pivotal movement of the frames.

I The advantage in using tires of rubber or yieldable 'material on the pulleys which are 'stem 15 or the bearing 83 does not interfere with p brought into engagement with each other will impossibleto bring the edge as close to the line 'c.casit is with the rubbertired pulleys because V the 'driving'friction of the driven pulley would be removed; r

rollers is provided with matched grooves or corrugations'as indicated at 93 and which provide corresponding grooves in the abrasive belts. The toolto be sharpened is drawn transversely across the belt but it will be noted that on one side one portion of the edge is being ground while on the opposite side another portion of the edge, not oppositethe first portion, is being ground. This avoids overheating the edge of the tool in the grinding operation and avoids impairing its temper. Another form of friction roller is indicated in Fig. 9 that may be substituted for rollers 19 and 25. The surface of this roller is provided with a series of spiral grooves 95 which increase the air Lcirculation where the abrasive belt enroller and assists in dissipatingthe heat." f

This invention may beapplied in a variety of forms in addition to that shown in the drawings and it may be adapted for polishing, grinding or other abrasive work. V V The structure of the invention may be used as shown, or its component'partsmay be used in other forms of grinding machines and in ma chines with other types of drive.

Having thus described my invention, I claim:

1. In a tool grinder a single base plate having a pair of spaced sockets and an aperture centered 45 In Fig.8 therollers 9|. and 92 are substituted forgthe'rollers l9 and 25. The surface of'these in one of said sockets, a pair of frames pivotally supported solely by said base plate through said sockets, a pair of pulleys in each frame and an abrasive belt mounted on each pair of pulleys for engaging the work at the same time, an arm pivoted to the frame opposite the aperture and exposed through the aperture, a shaft for one of said pulleys extending through a slot in the frame opposite the aperture and supported by said arm and a spring forcing said arm into the grinding position relative to the other frame.

2. In a tool grinder, a frame with a pair of rollers having grooves in their surface, a second frame with a pair of rollers having ridges to match the grooves of the first rollers, an abrasive belt mounted on and conforming to the grooves of each pair of rollers, said belts beingangularly disposed and arranged to meet opposite said rollers, the tool being passed between the belts and said rollers.

3. A tool grinder comprising a base plate having a pair of spaced apertures therein and an arcuate slot centered about each of said apertures, a pair of frames, each comprising a housing for a pair of spaced pulleys and an abrasive belt mounted on each pair of pulleys, each of said housings having. a hollow stem pivotally mounted in said apertures against said base plate, one of the pulleys of each frame having a shaft otally securing said frame by a clamp in said arcuate slot to said base plate with the pivot centered in said aperture, said frame being supported solelyv by said base plate, a shaft for one of said rollers located in a slot in said frame opposite the pivotal aperture of the base plate, A an arm pivoted to said frame and supporting said shaft at its free end and a spring engaging said arm to force the belt into the grinding position.

ADOLPH O. SCHAEFER. 

